This invention relates to hoses for dispensing fluids from one tank into another, one of the tanks being attached to a vehicle. It has particular application to fuel dispensers of the sort located in automotive service stations. Such dispensers typically include a dispenser body which includes a fluid mass flow meter and a display for showing the volume of fluid dispensed and the price, a manually operable nozzle, and a hose assembly attaching the nozzle to the dispenser. The hose assembly includes a flexible hose having fittings at each end, for connecting the hose to the dispenser and to the nozzle. In a traditional dispenser, a single hose assembly is connected to the side of the body of the dispenser. In a more modern multi-product dispenser, several hose assemblies are attached to an overhead canopy on the dispenser body.
In nearly all service stations in the United States and many in other countries, a breakaway coupling is installed in the dispenser's hose assembly to avoid damage to the pump or dispenser in the event of a drive-away. The breakaway coupling is typically installed in one of two positions in the hose assembly: at the dispenser in multi-product overhead dispensers and at the nozzle for traditional dispensers.
In the multi-product dispensers, the breakaway coupling is typically attached to a short connector hose (known as a "spacer hose" or "whip hose") which is in turn attached to an overhead arm on the dispenser. A "curb" hose is then connected between the breakaway coupling and a manually operated dispensing nozzle. The curb hose is generally over six feet long, typically eight to twelve feet long. This arrangement is shown for example FIG. 1 of Wilder et al., U.S. Pat. No. 5,564,471.
In a traditional dispenser, one end of the curb pump hose is attached to a side or lower portion of the dispenser body, and the other end is attached to the breakaway coupling. The breakaway coupling is attached to the nozzle by a short spacer hose (whip hose). The length of the curb pump hose is similar to that in the multi-product dispenser. Examples of this arrangement are shown in Fink et al., U.S. Pat. No. 5,365,973, and Nitzberg et al., U.S. Pat. No. 4,827,960.
Breakaway couplings are manufactured by many companies and have various constructions. All include two pieces which are intended to uncouple when a vehicle drives away from the dispenser without removing the nozzle from the fuel tank filler pipe. The breakaway coupling is designed to close both the long curb pump hose and the short hose, so as to prevent spillage of fuel in the hoses. By Underwriters Laboratory standards, the breakaway coupling must uncouple under an axial load of no more than three hundred fifty pounds. In practice, breakaway couplings have typically been found to uncouple at loads of from about two hundred fifty pounds to about four hundred pounds. Larger equipment may be provided with breakaway couplings having higher rated breaking forces. Examples of breakaway couplings are found in our U.S. Pat. No. 5,141,014 and the foregoing patent to Wilder et al.
Breakaway couplings are supplied not only on standard fuel dispensers but also on vapor recovery dispensers of both the balance type and the vacuum assist type. In both types of vapor recovery dispensers, coaxial hoses are provided. In the balance type, fuel flows through the central hose and vapor returns through the outer hose. In the vacuum assist type, the fuel flows through the outer hose. A typical vapor recovery hose is shown in Walker et al., U.S. Pat. No. 5,156,191. The cast spider shown in this patent in a balance-type vapor recovery hose is typically used in a vacuum-assist hose, and a simple bent strip spider is typically used in the balance type.
The breakaway couplings for vapor recovery hoses typically close only the fuel-carrying hose when they uncouple, although some close both hoses. Examples of such breakaway couplings are found in the foregoing patents to Fink et al. and Nitzberg et al., as well as in Carmack, U.S. Pat. No. 4,763,683, Carow et al., U.S. Pat. No. 5,209,262, Healy, U.S. Pat. No. 5,297,574, Guertin, U.S. Pat. No. 5,615,706, and Richards et al., U.S. Pat. No. 5,570,719.
With either type of dispenser and any commercially available breakaway coupling, when a drive-away occurs, the hose assembly will straighten out as the vehicle moves away. The spacer hose will bend to allow the breakaway coupling to be aligned with the curb hose for a straight pull on the breakaway coupling.
We have observed that under tension, fuel delivery hoses stretch far more than has heretofore been recognized. As the vehicle continues to move, the hose stretches by ten to twenty percent or more of its length, storing a large amount of energy in the hose. A ten-foot non-vapor recovery gasoline hose may stretch as much as three feet or more before the breakaway coupling separates. A heavier vacuum-assist or diesel fuel type may stretch less but store as much energy. A balance-type vapor recovery hose may stretch much more.
When the breakaway coupling separates, the stretched hose will sling, fling, and whip the hose in all directions with considerable force, with one section of the breakaway coupling at the free end of the long curb pump hose. If the breakaway coupling separates by the dispenser, the force will carry the free end in an erratic path toward the vehicle and can damage the vehicle, injure its occupants, and endanger anyone standing in the area. If the breakaway coupling separates by the vehicle, the curb pump hose will move erratically toward the dispenser and can damage the dispenser and injure anyone standing in the area of the dispenser.
It may be noted that gasoline-dispensing nozzles are generally provided with spouts which are also designed to break off in the event of a drive-away. The break-off load is designed to be about one hundred fifty pounds when the spout is at a right angle to the direction of force. Although a drive-away does not generally result in the spout's being subjected to a sufficient force at this angle to cause the spout to break off, when it does the nozzle is flung back toward the dispenser. Because the nozzle weighs much more than the breakaway (two to three pounds rather than a few ounces), the danger posed by the nozzle when its spout breaks is even greater than that posed by the breakaway when it uncouples.
After a drive-away occurs, the hose has been internally damaged, and the breakaway coupling is frequently damaged. Proper practice is to replace the hose following a drive-away. Failing to replace the hose may result in leakage through the fabric reinforcement of the hose and failure of the hose. The breakaway coupling can be reassembled if it is not damaged. Failing to replace a damaged breakaway coupling, however, may result in leakage around the breakaway coupling or improper operation of the breakaway coupling. The nozzle and its spout must also be inspected for possible damage.